1. Field of the Invention
The present invention relates to a clutch with friction plates, and in particular, to a polygonal clutch assembly housing polygonal friction plates.
2. Description of the Related Art
Multiple disk clutches for engaging and disengaging driving torque between input and output assemblies are known. Such clutches show adequate resistance to high stresses. Yet, those clutches as presently known exhibit several failings including resultant turbulence in connected transmissions and reduced clutch efficiency.
In traditional multiple disk clutch assemblies, an outside periphery of a first set of axially arranged friction disks are connected to an inside periphery of an outer clutch housing by spline connections. Similarly, a second set of friction disks, interposed between the first set of friction disks, are connected by spline connections between an inside periphery of the second set of friction disks and an outer periphery of an inside clutch hub. As arranged, the first and second sets of friction disks are free to move axially while being confined to rotate with the outer clutch housing and the inner clutch hub, respectively. Thus, when the first set of friction disks are pressured into contact with the second set of friction disks, the outer clutch housing rotates with the inner clutch hub thereby transmitting torque and rotation between associated input and output shafts. Several problems, however, are prevalent with such a configuration.
First, the spline connections cause turbulence in the connected transmissions. As the splines rotate through the hydraulic oil used to engage the clutch, the hydraulic oil foams. Such foaming detracts from the performance of the transmission. Second, peening of the splines reduces clutch efficiency. After frequent loading and unloading of the splines during operation of the clutch, the splines experience permanent deformation or peening of the contacting surfaces of the spline. This peening reduces the surface area of contact between the driving clutch housing or driven hub and the corresponding friction disks. Consequently, after peening of the splines, traditional clutch assemblies must transmit a given torque over a smaller surface area thereby reducing clutch efficiency. In response, heavier, thicker gauge splines must be used to resist the negative effects of peening. Unfortunately, thicker splines increases the weight of the clutch.